Blood collecting devices, known as phlebotomy tubes, are usually evacuated tubes that are inserted into syringes to collect blood from a vein. Typically, several such tubes are sequentially inserted into a syringe while that syringe remains injected into a patient. Thus, the tubes usually have gripping means built into the tube to allow their manipulation in the manner stated. That is, the outside of the tube is the gripping surface. However, further processing of the tubes is needed after blood collection, and any extensive gripping portion can be objectionable if it gets in the way of such processing. Particularly this becomes true if the collecting container is reduced in size, as then a handle must be added that serves no other function.
Thus, it would be convenient if a phlebotomy tube could be provided with a removable handle that is used only when the tube is put into or taken out of the syringe.
Removable handles have been typical of drug-injecting syringes. Generally such handles involve a friction fit with the piston used to push the drug out of a prepackaged container. Examples of such a construction are shown in, e.g., U.S. Pat. Nos. 3,045,674 and 4,507,117, as well as German Patentschrift No. 218,668. Such friction fit, however, is not a very secure engagement, so that there is no surety that accidental disengaging will not occur.
To improve upon such problems of friction fits, a rotating latch mechanism is described for a drug injection syringe in U.S. Pat. No. 4,677,980, that rotates 90.degree. between an engaged connection, FIG. 9, and a disengageable connection, FIG. 10. However, this construction renders it difficult to ascertain whether the handle is locked or not, as both conditions present the same overall appearance of the handle vis-a-vis the rest of the device. That is, the handle is rotated about a common axis with the syringe so that its apparent geometry vis-a-vis the syringe does not markedly change so as to suggest it is unlocked.
As far as can be ascertained, removable handles have never been proposed for phlebotomy devices, prior to this invention. Such a fact tends to discourage any reduction in size of the phlebotomy device, since the built-in gripping surface alone mitigates against size reduction.
Thus, prior to this invention, there has been a need for a removable handle for either a phlebotomy tube or a piston of a drug-injecting syringe that avoids the above-noted problems.